Dental X-ray focusing instrument



DENTAL X-RAY FOC USING INSTRUMENT Filed Aug. 22, 1932 INVEN-roR Henry/7. arfzvzz.

walme. wm

nip ATToRNEY `30 Having these matters in mind it has been an Y35 ment during exposure to the rays that distortion,

Patented Aug. 22, 1933 1,923,669

UNI-TED vSTATES Parar ri g DENTAL X-RAY FOCUSING INSTRUMENT Henry H. Harrison, `New York, N. Y. Application August 22, 1932. Serial No. 629,782 4 Claims. (Cl. Z50-34) This invention relates to radiant energy apwith the invention, indicating its application. paratus, and more particularly to an instrument Figure 2 is a peISDeCVe VleW 0f 011e ferm 0f for holding a photographic lm while being exthe implement ShOWiIig a COIlVeIllODal type f posed to actinic rays derived from powerful elecfilm held therein. trioai apparatus, known as Roontgen or X-ray Figure 3 is a similar perspeotlve vleW of anmachines, with special reference to taking photo- Olter itrn of tle3 dflevicdm,l t the .nstrmets graphs of teeth in the profession of dentistry. are efraglyld pasetcsem-W from In taking X-ray pictures of a tooth to deupper left and lower right posterior regions, the

at n ngle Wl@ th? tooth due to the omweg upper right and lower left regions, upper left con om O f the mterl of me mouth and thls and lower right anteriorA regions, and for the angle varies m accordance with the anatomical upper richt and lower left anterior regions of structure of the region in which the tooth is lothe moul Y cated' Each individual instrument consists of a frame In Order to Obtam an accurate Sclagraph of a 1G, which by preference is shown as` generally tooth free from dlstortloni an .Operator mut triangular, but obviously may be of any other compensate thls angle by dlrectmg the gomme suitable shape, its upper edge or vapex 11 having .rays .at mgm angls to, a target representmg an an inturned clip 12, while centrally on the lower 5 lmagmary plane bisecting the angl? beweenhe edge or oase 13 is a similar but reversely turned lm and axis of the tooth undergomg mvestlga clip 12', these parts together constituting a holder lon for a nlm-pack F.

An experienced operator, using the utmost Extending from one end of the base 13, at an Care can neve? pe Certa'm under the clrcum angle of approximately 115 degrees, is a bar 14 80' stances, of obtamlng accurate results, as there is` having a member 15 raised at an angle of 135 no presently known method of exactly determindegrees, acting as a connector for the focus dimg the Correct angle at Whlch the rays Should be recting arm 16 which extends from the connectdirected.

ing member 15 at an angle of 13G degrees.

Adjacent the bar 14 is a short stabilizer lug 17 85 ObJee 0f the present IHVeIllOIl JC0 DI'OVlde a dedisposed at an angle of 120 degrees with refervice by the use of which an X-ray dental lm ence to the holder 10 and adapted to be held by may be properly positioned with reference to om the nngers in adjusting and retaining the instruparticular tooth, and retained in such adjustment in the mouth, the come@ position of the stabilizer being in direct alinement with the longitudinal center line of the tooth; all these several parts are of integral construction, preferably of thin but rigid non-tarnishable metal.

A dental film E' of any standard type is inserted (l elongation, foreshortening, etc., etc., are eliminated.

A further feature is in the provision of means whereby the correct angle of ray penetration is Y40 mechanically determined, irrespective 0f the DO- between the iat face of the frame l@ and clips 95 sition of the tooth, and the rays directed at a 12-12 and placed in the mouth. The edges of right angle to a median plane between the center the frame and nlm rest against the tissues at the line of the tooth and the film. roof of the mouth and end of the tooth as seen Another purpose is to produce an extremely diagrammatically in Fig. 1, in which position the simple instrument for attaining the foregoing plane d of the film is 60 degrees from the axis results, the instrument being easy to apply and or center line b of the tooth T. effective in operation. As is well known a correct image of the tooth These important objects are accomplished by can only be obtained when the light rays from the novel construction, combination and arrangethe machine M are focused oro a plane o half Way ment of parts hereinafter described and illusbetween these peints, Ordinarily 30 degrees from trated in the accompanying drawing, constitut- JEhe lm and GOOL and the T3375 Strike the Plne ing a material component of this disclosure, and bisecting these angles, squarely at an angle of in Whichzdegrees along the line d, which corresponds Figure 1 is a side elevational view of an em- With the plane Of the OCUS finding arm 16 and 110 bodiment of an implement made in accordance by Which the rays Should be guided- To understand exactly what this instrument does and how it does it, it will be useful to describe the operation of taking a dental Roentgenogram at the present time.

The operator puts the X-ray` film in the patients mouth opposite the tooth to be X-rayed, directing the patient to press against the lm with the thumb in order to hold the film in position.

When this is done, the film is bent and distorted; and, inasmuch as a Roentgenogram is really a shadow picture, it can readily be seen that when the shadow of a tooth is thrown on a bent or distorted surface, the shadow will necessarily also be distorted. f

It should also be noted that whenfilm is placed in the mouth, anatomical conditions cause the film to assume a position at an angle away from the tooth to be X-rayed; this angle varying in the different positions of the mouth.

The operator is aware of the existence of this angle. He knows that he will elongate or foreshorten the shadow picture if he uses the tooth or the film as his target for the X-ray; He therefore endeavors to find an imaginary line half way between the tooth and the nlm, and uses this as his target for the X-ray.

But, owing to the variations in angles formed in different mouths, and in different positions in the same mouth, it can readily be seen that the focusing of the X-ray is dependent entirely on guess-work; and as a result of this, Roentgenograms are produced', even by competent men, which are either elongated, foreshortened, or distorted in various ways, sufficiently to render the Roentgenogram almost useless to one who strives for exactness in his work.

By reason of the angulation of this instrument, as will be seen in the drawing an X-ray directed against the tooth to be examined, parallel to the focus directing arm, will strike squarely at the imaginary line or target and assume a perfect focus.

From the foregoing it will be seen that the device constitutes a very efficient aid, not only in positioning and retaining the film, but also in directing the rays, causing them to properly focus and produce accurate images free from distortion.

Also from the foregoing it will be seen that a simple device for this purpose has been disclosed in the preferred form of its embodiment, but it is not desired to restrict the details to the exact construction shown, it being obvious that changes, not involving the exercise of invention, may be made without conflicting with the scope of the appended claims.

Having thus described the invention, what is claimed as new and desired to secure by Letters Patent, is:-

1. A dental film pack holder comprising an open triangular frame having hook clips at its apex and base, a rigid focusing arm reaching from theebase of said frame at a definite angle thereto, and a stabilizer on said frame adjacent said arm.

2. A dental film pack holder comprising a triangular frame having hook clips at its apex and base, and a focusing arm rigid with the base and extending therefrom at an approximate angle of 115 degrees with the base.

3. A dentalv film pack holder comprising a trangular frame having hook clips at its apex and base, a focusing arm on the base of said frame extending at an angle of approximately 115 degrees from the plane of the frame, and a. stabilizer extending from the `nase of said frame at an angle bisecting the angle of said arm and plane of m said frame, all of said elements being integral.

4. A dentalv film pack holder comprising a trangular frame provided with pack retaining clips,

a focusing arm, and a stabilizer, said arm and stabilizerk being rigid. with said frame and fixed M5 at an angle of approximately 115 degrees from one another.

HENRY H. HARRISON. 

